News Turkish airlines plane crashes in Amsterdam

[n122vu]

I simply disagree with the fuel exhaustion theory. Unless evidence is revealed to suggest that as the possible cause, my money is on some sort of mechanical failure in the engines.

 

[lennartsmit]

I'd say human error. There was a guy who survived the crash on the news. He said he saw that the plane was at about 20-30 meters (100 feet) and then heared the engines fire up. After that they crashed on the tail. Also there was no radiocontact about any failures or fuel-shortage.
The nationalities of the dead are known, 4 americans, 5 turks, no names though.

 

[cjp]

The nationalities of the dead are known, 4 americans, 5 turks

The Westboro Baptist Church seems to have updated their hate messages to the news that there are no dutch victims:
Before
After
(both are mirrors)

 

[Urwumpe]

According to German news, two of the American deaths are Boeing employees... the irony in the tragedy.

 

[ozone]

The Westboro Baptist Church seems to have updated their hate messages to the news that there are no dutch victims:
Before
After

Please understand that even among very conservative religious groups these people are considered "special", They are really only one extended family.
http://en.wikipedia.org/wiki/Westboro_Baptist_Church

 

[cjp]

http://en.wikipedia.org/wiki/Westboro_Baptist_Church[/URL]

Yes, I understand.

Back to the main topic:

I heard an interview on TV of one of the surviving passengers, who said that the plane was flying low, then suddenly fell down unexpectedly, and then the engines went full-power, just before the plane crashed. There were also eye-witnesses on the ground who reported the engines going full-power just before the crash.

I don't think anything was wrong with the engines or the fuel. Maybe the wings stalled, or there was a sudden downward wind.

I'm not a meteorologist, but intuitively I wouldn't expect the downward wind. The weather was quite calm that day. On the ground, visibility was OK, but there was a low layer of grey clouds completely covering the sky. Any vertical wind would have caused visible irregularities in the shape of the cloud layer, and such irregularities were not present.

Then why would the plane stall, with an experienced pilot flying the machine? Maybe a defect velocity indicator? But then the artificial horizon should also be defect, or otherwise the pilot should automatically see when something is wrong. I can imagine things were already going wrong when the plane was still inside the cloud layer, so that the pilot had to rely on instruments only.

Black box results are expected soon; they should give some important information.

 

[T.Neo]

The Westboro Baptist Church seems to have updated their hate messages to the news that there are no dutch victims:
Before
After
(both are mirrors)

Both messages are sick.
Just sick.

 

[Urwumpe]

I don't think anything was wrong with the engines or the fuel. Maybe the wings stalled, or there was a sudden downward wind.

Also, remember that the 737 has the tendency to pitch up rapidly on stall - and loose even more lift to drag.

Which would explain why the 737 came down almost vertical.

The hull of a airliner can take a lot of stress, before it breaks. Just by rough terrain, this can not be explained. But if the 737 dropped almost vertical, even at lower speeds, it can.

I just wonder why the 737 became too slow. The pilots should have noticed the increased vibrations already early, if the passengers also noticed it. And if the engines still spooled up during stall, it seems like there was at least one reaction... did the pilots have the autopilot accidentally active?

 

[Moonwalker]

Then why would the plane stall, with an experienced pilot flying the machine? Maybe a defect velocity indicator?

The airspeed indicators work independently. Thy are connected to their own pitot tubes and static ports, captain and first officer.

But then the artificial horizon should also be defect, or otherwise the pilot should automatically see when something is wrong.

The artificial horizon has nothing to do with the airspeed indicator. The artificial horizon is driven by a gyroscope, while the airspeed indicator is a pressure instrument. Or do you mean that the entire PFDs (Primary Flight Displays) went off? In this case there is still a standby altimeter, airspeed indiactor and artificial horizon located on the left hand side of the center main instrument panel. The standby airspeed indiactor is connected to the auxiliary pitot tubes by the way.

I think we should wait for the investigation results. Shoptalk won't find out anything.


-----Post Added-----

The hull of a airliner can take a lot of stress, before it breaks.

Depends on how you define "a lot of stress". For passenger jet aircraft the g-force limit is mostly about -1g to +2,5g (and only +2g with flaps set).

Also, remember that the 737 has the tendency to pitch up rapidly on stall - and loose even more lift to drag.

Only late into the stall if you do not push, which is the case for some airplanes. Intended stalls during test-flights are no problem for the 737, just like for almost any civil aircraft which gets an approval.

 

[Urwumpe]

Depends on who you define "a lot of stress". For passenger jet aircraft the g-force limit is mostly about -1g to +2,5g (and only +2g with flaps set).

This are aerodynamic limits, but not structural. Structural limits are in general about 5G for the wing loading, and slightly more for typical bending moments. A 2G maneuver with flaps extended would cause a high speed stall already.

A typical hard landing would not crack the hull, and most cases of failed nose gear or tail contacts also don't cause such visible damage.

 

[Moonwalker]

A typical hard landing would not crack the hull, and most cases of failed nose gear or tail contacts also don't cause such visible damage.

The 737 did not land hard, it crashed.


-----Post Added-----

And if the engines still spooled up during stall, it seems like there was at least one reaction... did the pilots have the autopilot accidentally active?

If it was an autoland, it was not accidentally active. A stall would be unlikely in this case, and for what reason? If it was a manual landing, it is rather unlikely that the autopilot was accidentally active, especially during short final. The auto throttle system does work indipendently from the auto pilot anyway, in case it is set to speed hold. Only in VNAV mode, the auto throttle works in conjunction with the auto pilot and flight management computer (vertical navigation, which includes speed control, but only used for climb, cruise and early descent anyway).

 

[tblaxland]

A typical hard landing would not crack the hull, and most cases of failed nose gear or tail contacts also don't cause such visible damage.

Maybe not the hull, but the tail is a definite possibility:

 

[Moonwalker]

Maybe not the hull, but the tail is a definite possibility:
YouTube - Airplane Crash

Yes, but not only the tail. Actually, only parts of the fuselage can take some stress. But it mostly cracks/breaks at certain points anyway (tail, mid section and nose).

By the way, the g limitations during flight (+2,5g / +2g with flaps set, for most Boeing and Airbus aircraft) are not only aerodynamic limts, but also structural limts. That is why the flight envelope protection of Airbus aircraft does not allow to exceed a bank of 67° (2,5g) and 45° while flaps set (2g). Also, you do not command an elevator position by pushing or pulling the side stick, you command a load factor change. I read that once again (casually) today, while studying my original Airbus documents in preparation to fly it in MSFS again the next week (Wilco Airbus Series).

 

[Urwumpe]

Moonwalker: Can you verify if these limits are really structural? The A300 ZERO-G already pulls 2G during the pull-up phase of a parabola.

 

[Bj]

Maybe not the hull, but the tail is a definite possibility:
YouTube - Airplane Crash

wow, I wonder what his vertical speed was, that it would make it break like that.

 

[Moonwalker]

Moonwalker: Can you verify if these limits are really structural? The A300 ZERO-G already pulls 2G during the pull-up phase of a parabola.

According to Airbus it is aerodanymical and structural, but without further explanations even within the operating manuals. It is generally a good advice not to exceed these limits on such big airplanes (although the famous barrel roll of the 707 back in the late 1950's is awesome).

But 2g is still within the limit anyway. And I don't think those zero g flights get significantly beyond -1 g / + 2,5 g. But the A300 has no fly-by-wire system and flight envelope protection that prevents pulling more g's (fly-by-wire was first tested for the "new" A320 on an A300-600 as far as I know). Fly-by-wire would be a bad idea for zero g flights (pitch limit 15° in descent and 30° in climb).

 

[Hielor]

According to Airbus it is aerodanymical and structural, but without further explanations even within the operating manuals. It is generally a good advice not to exceed these limits on such big airplanes (although the famous barrel roll of the 707 back in the late 1950's is awesome).

The 707 aileron roll didn't exceed any limits. It was a 1g maneuver, apparently.

 

[Moonwalker]

The 707 aileron roll didn't exceed any limits. It was a 1g maneuver, apparently.

You can do it with 1 g but you need a pullout of about 2g at the end I think. If you know how to do it, it is safe, relatively, and does not exceed limits.

That's the limits of the barrel rolled 707 by the way:

http://www.flightsim.com/feature/barrel/vn.gif

 

[Andy44]

According to the pilot who rolled the 707, Tex Johnson, it was a 1G maneuver. You just have to have enough altitude when you begin the roll.

BTW, 2.5 G sounds awful low for a structural limit on an airplane, especially one has to carry passengers. Turbulence alone can exceed that for brief periods, and a Cessna 150 can take up to 6.6 G, although the operator's manual says the pilot should never exceed 4.4. While a jetliner should theoretically never need to be bent so hard, it's not difficult to imagine a few dozen situations in which it has to be able to handle it.

 

[simonpro]

Moonwalker: Can you verify if these limits are really structural? The A300 ZERO-G already pulls 2G during the pull-up phase of a parabola.

Pull up is typically 1.8g, pull out is around 2g, I've seen the g-meter go up to 2.4g on a turbulent day though.
Anyway, the airbus zero-g was modified to cope with the high-g environment. Iirc, something was done to the hydraulic system and to the tailplane. Most importantly, though, the wing roots were heavily strengthened.

Apparently the pre-mod plane (which was in service with, i think, Lufthansa) would have been capable of flying the parabola, but it'd have been taken close to it's structural limit, so after every flight they'd have to C-check the entire plane. To my (somewhat limited) knowledge the original never-exceed limited were more than +4 and -3g, but I don't know the exact values.